HOEKPLAATS Dolomite (Pty) Ltd

Preliminary Groundwater Assessment: Portion 23 (A Portion of Portion 15) of the farm Hoekplaats 384 JR

DATE: October 2010 REVISION Final REFERENCE: 215_Hoekplaats COMPILED FOR: Umhlaba Environmental Consulting CC PO Box 731504 Fairland 2030 COMPILED BY: GROUNDWATER SQUARE Consulting Groundwater Specialists HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) Executive Summary

Umhlaba Environmental Consulting CC contracted Groundwater Square on behalf of Hoekplaats Dolomite (Pty) Ltd to compile a preliminary hydrogeological desk study investigation to provide guidance on any future groundwater studies that may be required. The proposed opencast dolomite mine is on situated Portion 23 (a portion of Portion 15) of the Farm Hoekplaats 384 JR approximately 15km south-west of Pretoria. Mining will entail a conventional drilling and blasting opencast operation. The targeted mining area will be approximately 300m x 500m in size and approximately 40m deep. The following main conclusions were reached:

 The regional dolomitic aquifers was highlighted as a significant source of drinking- and irrigation water;  Locally the direction of groundwater movement from the site is in a north-westerly direction towards the Hennops River and the Aalwynkop Spring. The northern regions of the quarry floor is expected to be at lower elevations than the Aalwynkop Spring;  The depth of mining will be ±30m below the natural groundwater level. Groundwater will have to be pumped from the pit;  The Zwartkop dyke may potentially compartmentalise the aquifers (depending on its weathering depth) to restrict the extent of the groundwater dewatering cone around mining;  It is anticipated that the aquifer within the proposed mining area may be low yielding due to being chert-poor and with limited leaching of the dolomites (to the depth of mining);  Borehole EUB-6 is situated on Ptn.23 of the farm Hoekplaats 384 JR. Six external user’s boreholes were indentified within a 1km radius of the property. The reported total daily abstraction recorded within a 1km of Portion 23 totals approximately 38m3/d.

Once the mine intersects the natural groundwater table, groundwater will be pumped from the pit, resulting in a cone of dewatering developing around the pit. Although the extent of dewatering may be limited/restricted due to various factors, the potential impact on external users’ boreholes and impact on base-flow to the Hennops River and Aalwynkop Spring requires further investigation. The main recommendations for further work therefore focussed on the utilisation of a numerical groundwater flow model to determine/evaluate the potential impacts on external users’ borehole yields and groundwater base-flow toward the Hennops River and the Aalwynkop Spring. Dedicated hydrogeological boreholes should be drilled and pump tested to determine hydraulic aquifer parameters, for inclusion in the numerical model.

GROUNDWATER SQUARE Page ii HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) Table of Contents

Executive Summary ...... ii Table of Contents ...... iii

1. INTRODUCTION ...... 4 1.1. Background...... 4 1.2. Mining Information ...... 4 2. TERMS OF REFERENCE ...... 4 3. SETTING ...... 5 3.1. Regional Setting ...... 5 3.2. Rainfall...... 6 3.3. Land-use...... 6 3.4. Morphology and Drainage ...... 7 3.5. Soils ...... 7 3.6. Local Setting...... 7 4. GEOLOGY...... 9 4.1. Regional Geology ...... 9 4.2. Local Geology...... 10 5. HYDROGEOLOGY...... 11 5.1. Regional Hydrogeology ...... 11 5.2. Local Geohydrology...... 13 5.2.1. Groundwater Use ...... 13 5.2.2. Hydrocensus...... 13 5.2.3. Depth to Groundwater Level and Hydrostatic Fluctuations...... 14 5.2.4. Groundwater Flow Direction...... 16 5.2.5. Aquifer Yielding Potential ...... 16 5.2.6. Groundwater Quality...... 16 5.2.7. Surface Water Quality ...... 18 6. POTENTIAL IMPACTS...... 20 6.1. Identification of Potential Impacts...... 21 6.2. Discussion of Potential Impacts...... 21 7. RECOMMENDATIONS ...... 22

References ...... 23

GROUNDWATER SQUARE Page iii HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

1. INTRODUCTION 1.1. Background Umhlaba Environmental Consulting CC recently compiled an Environmental Scoping Report for HOEKPLAATS Dolomite (Pty) Ltd. The proposed opencast dolomite mine is situated on Portion 23 (a portion of Portion 15) of the Farm Hoekplaats 384 JR approximately 15km south-west of Pretoria. Umhlaba approached Groundwater Square undertake a preliminary hydrogeological investigation. It was decided to perform a desk study, which could provide guidance (and serves as the basis) for any future groundwater studies that might be required.

1.2. Mining Information The targeted mining area will be approximately 300m x 500m in extent with a maximum projected depth of ±40m. The proposed mining will entail a conventional drilling and blasting opencast operation with the frequency of blasting being dependant on product demand. Rock will be crushed and screened to include the following products:

 19mm concrete stone;  13.2mm concrete stone;  9.5mm concrete stone;  ≤6.7mm super-sand.

The installation of services will include the construction of the following:  Plant;  Settlement dam;  Workshops and fuel facilities;  Administration offices;  Demarcation of the salvage yard;  Connection to the water and electricity supply;  Sanitation facilities.

2. TERMS OF REFERENCE Based on the project objectives, the following Terms of Reference were proposed by Groundwater Square on 07/08/2010:

 Collate and perform desktop exercise of available geological and hydrogeological maps/reports pertaining to the study area;  Compile a hydrogeological interpretation of the expected groundwater system;  Identify likely impacts in view of the Dolomite Mine design and geological drilling (no impact assessment was required);  Describe dolomite compartments and decant elevations from these compartments;  Based on the outcome of the desktop exercise, determine whether a full-scale investigation will be required (and the nature thereof).

A site visit was undertaken on 15/09/2010, followed by a survey of external users to confirm certain aspects of the desktop assessment. A sample of the nearest borehole was collected to analyse the water quality. Disclaimer – The state of hydrogeological knowledge was presented as accurately as possible using available information. Groundwater Square exercised due care and diligence in gathering and evaluating relevant information. Groundwater Square will not accept any liability in the event of encountering unexpected aquifer conditions during mining and further investigations. Any unauthorized dissemination or reuse of the desktop study report will be at the user's sole risk and with the condition that Groundwater Square will not accept any liability for any and all claims for losses or damages and expenses arising out of or resulting from such unauthorized disclosure or reuse.

GROUNDWATER SQUARE Page 4 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) 3. SETTING Portion 23 of the Farm Hoekplaats 384 JR is located within the jurisdiction of the Tshwane Metro Council.

3.1. Regional Setting The subject area as shown in Figure 3.1 falls within quaternary catchment area A21B of the Upper Crocodile sub-area of the Crocodile (West) and Marico Water Management Area (WMA). The following key groundwater issues pertain to this part of the WMA:

 The southern dolomite outcrop,(parts of catchments A21A, B, D, F, G, H) is a hemispherical outcrop of dolomite to the east, north and west of the granite underlying ;  The dolomite forms mostly level/flat ground to the east and northeast of Johannesburg with extensive dry land agriculture and some irrigation, especially around Bapsfontein where a total of approximately 12km2 is irrigated (2004 estimate);  Maximum borehole yields exceed 40L/s (as deep as 250m). Average borehole yields vary from 2L/s to 10L/s. Water tables vary from <10m in vlei areas to >50m; 3  During 1995 the groundwater use was estimated at 21.9Mm , mostly for the purpose of abstraction for urban water supply (Centurion) and irrigation (Bapsfontein and Tarlton);  The dolomite represents an important aquifer with significant groundwater resources, hence the widespread abstraction. The potential for additional exploitation of the groundwater resources within the catchment may be considerable;  The aquifer contributes base flow to surface drainage, which flows into the ;  Groundwater quality is generally good. However, the dolomites are vulnerable to pollution, especially where karst conditions are present.Groundwater protection forms an integral part of catchment management in dolomite areas.

Figure 3.1 Regional setting The following key water issues were identified for this WMA:

 The water requirements of the area are increasing due to the spread of settlements and irrigation demands, especially in catchments A21A (20km to the east) and A21D (30km southwest). Available information indicates that groundwater resources are approximately 85% utilised, while GROUNDWATER SQUARE Page 5 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

surface water is fully accounted for;  Dolomite aquifers/compartments do not coincide with surface catchment boundaries and transect into the Upper Vaal and Olifants WMAs;  Groundwater abstraction from dolomite aquifers may cause the development of sinkholes.Areas where the ground is already unstable and water levels are allowed to fluctuate regularly, are particularly vulnerable to sinkhole development;  Several examples exist where sewage effluent is discharged into the surface drainage systems which flow across dolomite compartments in . Incorrect operation of the following sewage treatment works, can lead to pollution of the surface/groundwater systems in/around the Hennops River: o The 50ML/day capacity Hartebeestfontein water treatment works discharges into the easterly Rietspruit (formerly the Swartspruit) upstream of Rietvlei Dam; o The 38ML/day capacity Olifantsfontein water treatment works discharges into the Olifantspruit upstream of its confluence with the Sesmylspruit below Rietvlei Dam; o The 35ML/day capacity Sunderland Ridge water treatment works discharges into the Hennops River upstream of its confluence with the Crocodile River;  Additional water quality impacts on local groundwater systems include: o Below the confluence with the Olifantspruit, the Sesmylspruit features the man-made Centurion Lake with known quality problems such as algal blooms; o Informal settlements lacking adequate water and sanitation services (e.g. e-coli, nitrates and salinity); o Agricultural practises.

3.2. Rainfall According to Midgeley (1994), catchment A21B (527km2) has a mean annual precipitation (MAP) of 672mm/a and a mean annual evaporation (MAE) of 1700mm/a.

3.3. Land-use The surrounding land-uses include (refer Figure 3.1 & Figure 3.2):

 Urban and industrial areas, such as Ladium, Erasmia, Valhalla, Wierdapark and Sunderland Ridge;  Numerous agricultural/smallholdings, such as Gerardsville, Raslouw, Sunderland, Deltoidia, Hoekplaas and Mooiplaas.Irrigation takes place on the Mooiplaas and Hoekplaas smallholdings along the Hennops River. Poultry farms exist on Vlakplaats 354 JR, Knoppieslaagte 385 JR and 355 JR;  The Velmore Hotel is located less than 1km to the east along the M26;  The Bayete Function Venue and Day Spa is located on Ptn.4 of Hoekplaats 384 JR some 800m to the north-northwest;  The neighbouring property to the west, along the M26, features The Cheese Shop and the Take a Break Nursery and Coffee Shop;  Hennops Brick & Pave brick works is located to the immediate north of Portion 21 of the farm Hoekplaats 384 JR;  Catwalk Brick Works is located on Ptn.1 of Hoekplaats 384 JR on the opposite side of the M26;  An informal settlement is located some 2.5km to the southeast on Potion 7 of the farm Hoekplaats 384 JR;  The PPC dolomite quarry is located some 2km north-northeast on Schurweplaas 353 JR, roughly 1km west of Erasmia;  The Sunderland Ridge sewage works with a capacity of 35ML/day is located some 5km upstream from the subject area, immediately west of the confluence of the Sesmylspruit and the Rietspruit, on the southern bank of the Hennops River;  The Zwartkop Nature Reserve is located between Valhalla, the Sesmylspruit and the some 5km east of the subject area;  A domestic refuse site is located some 5.5km to the northeast, opposite the Zwartkop Race Track, next to a defunct dolomite quarry (Mittal) between the R55 and the Zwartkop Nature Reserve.

GROUNDWATER SQUARE Page 6 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) 3.4. Morphology and Drainage The drainage density (Kruger, 1983) does not exceed 2km.km-2 and is classified as “low” to “medium”. Stream frequency is also classified as “low” to “medium” (0 - 6stream.km-2). Catchment A21B is drained by the Hennops River and its tributaries namely the Sesmylspruit below Rietvlei Dam, the Olifantspruit which joins the Sesmylspruit south of Irene as well as the Rietspruit which confluence with the Hennops River coincides with that of the Sesmylspruit; and also the Swartbooispruit which joins the Hennops River upstream of its eventual confluence with the Crocodile River.

3.5. Soils The study area falls within soil mapping unit 11 of the Institute for Soil, Climate and Water (ISCW) broad natural homogeneous soil zone (BNHSZ) regions (Schulze et. al, 1997). This assigns a soil depth of 500 to 1000mm to 80% of unit 11. The remaining 20% of this unit is characterised by soil depths ranging between 100 to 400mm respectively. Unit 11 comprises of 60% SaClLm and 40% SaLm (sandy loam – 10 to 20% clay content) typically supports a medium drainage rate.

3.6. Local Setting Portion 23 of the farm Hoekplaats 384 JR, is located immediately south of the M26. It is 49ha in size. Grasslands are currently used for grazing purposes. The distance to the Hennops River varies between 410m to 810m to the north. Existing infrastructure on the property consists of a farmhouse which is currently occupied by a tenant. Figure 3.3 depicts pertinent site information.

Figure 3.2 Local setting The following comments relate to surface water and groundwater:

 As can be seen in Figure 3.2, the subject area is situated between the Hennops River and the Swartbooispruit which is located some 1.5km to the west. Another small non-perennial drainage line is located some 500m east;  The subject area falls within the boundaries of the Aalwynkop dolomitic compartment. The

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boundaries to this compartment which is also subdivided into a number of sub-compartments are largely constituted by dykes of low permeability (impermeable at depth) that act as hydrogeological barriers;  Outflow from the Aalwynkop compartment occurs as discharge from the Aalwynkop Spring to the northwest;  The site topography slopes to the north-northwest in the direction of the Hennops River: o The topography varies between 1428mamsl (south) and 1364mamsl (north along the M26), at gradients varying between 0.033 and 0.045; o To the west of the site, the topography slopes to the west in the direction of the Swartbooispruit, a tributary of the Hennops River.

2857750

Geological borehole

EUB-3

2858000 Dyke outcrop EUB-1

EUB-2 BH8 Water supply borehole Topography

2858250 BH6 EUB-6

BH7

BH5

2858500

BH1 BH4

2858750 BH3 BH2

P

o

r t i o

n

b

o

u

n

d

a

r y 2859000

2859250

2859500 94500 94250 94000 93750 93500 Figure 3.3 Pertinent site information

GROUNDWATER SQUARE Page 8 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) 4. GEOLOGY 4.1. Regional Geology The geology of the study area is portrayed in Figure 4.1 (extract from the published regional 1:50 000 geological map; 2528CC LYTTLETON).

Figure 4.1 Regional geological map The regional geology comprises of strata of the Chuniespoort and Pretoria Groups of the Transvaal Supergroup. The Transvaal Supergroup is characterised by its arcuate distribution around the Halfway House dome and a general dip of 150 to 250 towards the northeast and west. The Black Reef Formation (Vbr) which consists of a basal and upper quartzite separated by dark carbonaceous shale forms the basal unit of the sequence and is conformably overlain by the carbonates of the Malmani Subgroup. The Rooihoogte Formation of the Pretoria Group overlies the Malmani Subgroup disconformably. The Malmani Subgroup (Vmd) is subdivided into the Oaktree (chert-poor), Monte Christo, Lyttelton (chert-poor), Eccles and Frisco Formations (SACS 1980). Large tracks of land covering the dolomites are covered by a mantle of red silty soil and residual solution debris varying considerably in thickness. These were derived from recent dolomite solution and the weathering of older karst regoliths. The debris consists of angular fragments of chert and grit, sand, clay and manganiferous earth (wad) in various portions. The presence or absence of chert controls the topographic expression of the dolomite succession. The chert-poor units weather to a smooth topography covered by red silty to clayey soils devoid of chert. The chert-rich units weather to an uneven topography charaterized by dissolution openings, chert pinnacles and a permeable chert residue with red silty and brown manganiferous soils. Low drainage density is indicative of a high degree of leaching. A characteristic feature of the regional geology is the network of intersecting diabase and syenite dykes as well as syenite sills. These are narrow, vertical, intrusive formations subdividing the dolomite into various groundwater compartments. Leakage through dykes is likely to occur. The rate of leakage is controlled by the hydraulic gradient and the permeability of the dyke. As can be seen in Figure 4.1, the northern boundary of the property coincides with the east-northeast trending Zwartkop dyke. The northern-most portion of the property is partially transected by the GROUNDWATER SQUARE Page 9 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) southeast trending Pinedene dyke that seems to be displaced between the property’s western boundary and the M26 further to the west. The southern-most portion of the property is transected by a northeast trending dyke that cuts across both the Pinedene dyke and the Zwartkop dyke as well as the large syenite sill outcrop coinciding with the southern boundary of the cadastral farm Hoekplaats 384 JR. Figure 4.2 is a photograph of this dyke outcrop that was taken at the location indicated in Figure 3.3.

Figure 4.2 North-westerly view of Pinedene dyke outcrop on Ptn.23 of Hoekplaats 384JR The following comments relate to the likelihood of seismic activity:

 According to the Council for Geoscience (CGS, 1992) the region is identified as a Category V (MMS) with only a 10% probability of an event of magnitude 6 (MMS) being exceeded once in a period of 50 years;  It is important to note that the site lies outside of the three areas of greatest seismic hazard of South Africa (CGS, 1992);  The South African Bureau of Standards (SABS 1990) issued minimum building requirements to be implemented in areas it had identified as having inherent seismic risk. No requirements exist for the site.

4.2. Local Geology The following description of the local geology were based on 8 exploration boreholes that were drilled (see locations in Figure 3.3):

 The depth of exploration boreholes ranged between 19m and 50m deep (average 32m);  The only intrusive encountered/penetrated was in BH3, which recorded a syenite intersection between 15m and 16m deep;  Only one borehole, BH4 recorded a water intersection between 23m and 25m deep;  No soils were recorded in BH1, BH2, BH3 and to BH4. A soil profile ranging between 0m and 1m in thickness, and consisting of ferricrete, soil and leached dolomite gravels, were recorded in the remainder of the boreholes;  Leaching ranged between 5m and 17m deep (average 8.9m. The deepest levels of leaching were recorded in boreholes BH3 (17m) and BH4 (11m); GROUNDWATER SQUARE Page 10 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

 The lithological profile recorded in borehole BH5 [WGS84 S25.83078 E28.06007 1373mamsl] is presented in Table 4.2.

Table 4.2 Geological log – borehole BH5 0 - 1 Dark grey, medium, chert and leached dolomite fragments - boulders 1 - 2 Pink, medium, leached dolomite and minimal chert 2 - 5 Red grey, medium, leached dolomite and minimal chert 5 - 8 Grey, medium, jointed dolomite, signs of leaching and chert 8 - 15 Pink-red, medium, jointed dolomite, signs of leaching and chert 15 – 16 Pink grey, medium, jointed dolomite, signs of leaching and chert 16 - 17 Grey, medium, jointed dolomite, signs of leaching and chert 17 - 18 Dark grey, medium, jointed dolomite, signs of leaching and chert 18 -19 Grey-pink, medium, jointed dolomite, signs of leaching and chert 19 - 20 Pink grey, medium, jointed dolomite, signs of leaching and chert 20 - 22 Light grey, medium, jointed dolomite, signs of leaching and chert 22 - 23 Pink, medium, jointed dolomite, signs of leaching and chert 23 - 27 Grey-pink, medium, jointed dolomite, signs of leaching and chert 27 - 28 Dark grey, medium, jointed dolomite, signs of leaching and chert 28 - 33 Pink grey, medium, jointed dolomite, signs of leaching and chert 33 - 37 Grey-pink, medium, jointed dolomite, signs of leaching and chert 37 - 49 Grey, medium, jointed dolomite, signs of leaching and chert 49 - 50 Dark grey, medium, jointed dolomite, signs of leaching and chert

5. HYDROGEOLOGY 5.1. Regional Hydrogeology The dolomites of the Chuniespoort Group represent one of the most important aquifers in South Africa. According to the Johannesburg 2526 Geohydrologcial sheet, spring flow discharges from dolomites equates to 120.5Mm3/a. In comparison (Barnard, 2000), some 315 Mm3/a were utilised for irrigation from groundwater abstraction (41.5%), domestic use (3%), mining (50%) and municipal/industrial (5.5%). Leaching of the dolomite and the subsequent development of high to very high storage and permeable horizons is litho-stratigraphically controlled as the aquifer comprises of an extensive cover of residual solution debris and in places younger sediments which are underlain by karstified dolomite which is irregular and inhomogenic with hydraulic conditions varying from phreatic to confined. The karstified superficial zone of the strata acts as the main aquifer, even though fractures that often support high yields can extend to considerable depths in non-karstified dolomite. Intrusions varying in composition from syenite to diabase and dolerite subdivide the dolomite into compartments to form hydrogeological units. Groundwater gradients generally range between 1% and 2% when not influenced by large scale abstraction. Steps in the water level occur from one sub-compartment to another, validating boundaries. The low density of surface drainage networks in dolomitic areas suggests high recharge and significant underground flow which often supports high yielding springs located at the lowest elevation of a compartment in proximity to an impermeable boundary such as a dyke or lithological contact. Overflow or leakage through dyke features in low lying areas where these are weathered near the surface is a common occurrence. The following additional comments relate to the regional hydrogeology:

 The groundwater levels in dolomitic aquifers do not necessarily follow the topography: o The generally very shallow gradients are indicative of very permeable formations; o Consequently very deep rest levels may be found in areas of raised topography. Depths exceeding 100m below surface are not uncommon. Deep water levels in many compartments are however the result of dewatering by gold mines as well as overutilization for irrigation purposes;

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o The Groundwater Resources of the Republic of South Africa Map, sheet 1 & 2, 1995 indicate the average depth to groundwater as 20m to 30m below surface with a standard deviation range of 15m to 25m from mean;  The rate and extent of water level drawdown in response to abstraction from dolomitic aquifers are one of the critical factors in the development of ground subsidence and sinkholes: o It is an important consideration in establishing large scale abstraction schemes from the dolomites; o The risk of subsidence and sinkholes is greatest in areas of shallow groundwater levels (<30m) and where it fluctuates more than 6m in response to pumping;  Boreholes typical yields >5L/s for the area (karst aquifer - dolomitic strata): o The maximum recorded borehole yield for similar dolomitic aquifers was 126L/s; o Borehole blow yield information sourced from the National Groundwater Database (NGDB) between Latitude S25.75 to S25.89 and Longitude E28.00 to E28.15 (81 boreholes) ranged between 0.1L/s to 40L/s (mean=2.66L/s, median=2L/s);  Porosity and aquifer storage capacity (storativity) values are expected to decrease with depth. Several hydrogeological studies have confirmed this: o A study by Enslin and Kriel (1967) in the Carltonville area indicated that storativity values decrease from an estimated 9.1% (61m deep) to 1.3% (146m deep); o According to Bredenkamp et. al. (1995), the storativity of dolomitic aquifers generally varies between 1% and 5%;  Natural recharge from rainfall are typically in the order of 7% to 12% of rainfall on an annual basis as quoted by the following studies: o Bredenkamp (1995), ±7% of MAP; o Kok et. al. (1985) determined that recharge range between 8% and 19% (as a function of rainfall ranges on an annual basis), an average of 14% of MAP was calculated for the Rietvlei area; o Hobbs (1988) estimated recharge for the Irene catchment at 11.1%; o Vegter (1995) indicated the groundwater recharge for the study area to range between 11.2% (75mm/a) to 16.4% (110mm/a);  The Chuniespoort Group groundwater chemistry is summarised in Table 5.1 (223 samples): o Karst aquifers (dolomitic strata) have a CaMg-HCO3 character; o The natural quality is generally acceptable for any use; o Coefficients of variation greater than 200% for chloride, sulphate and nitrate suggest the presence of contamination in some of the samples.  A Ground Water Quality Management Index of “9” was calculated for the proposed mining area after the method of Parsons (1995; “Aquifer System Management Classification and Aquifer Vulnerability Classification”; WRC Report No KV 77/95). Based on this Index of 9, a high level of groundwater protection may be required;  The Groundwater Harvest Potential Map of the Republic of South Africa (DWAF, 1986) indicate the maximum volume of groundwater that may annually be abstracted per surface area to preserve a sustained abstraction, range between 50 000 m3/km2/a and 100 000m3/km2/a.

Table 5.1 Groundwater chemistry of the Chuniespoort group (223 samples) Variable Minimum Mean Maximum Standard Coefficient of Deviation Variation pH 5.8 7.6 9.5 0.4 5% EC (mS/m) 4.4 62.9 397 56 89% TDS (mg/L) 43.1 443.6 3402 403 91% Ca (mg/L) 1.0 52.7 436 54 102% Mg (mg/L) 1.0 35.4 223 31 88% Na (mg/L) 1.0 24.1 299 39 162% K (mg/L) 0.1 2.3 39 4.2 183% Cl (mg/L) 1.0 37.7 900 83 220% SO4 (mg/L) 1.0 70.5 2172 233 330% T.Alk.(mg/L) 8.0 177.3 664 94 53% NO3 (mg/L) 0.1 5.6 122 12.1 216% F (mg/L) 0.1 0.3 2.8 0.4 133% Langelier Saturation Index -4.7 -0.4 3.0 1.0 (LSI)_ Sodium Adsorption Ratio 0.03 0.5 2.9 0.5 100% (SAR)

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5.2. Local Geohydrology The proposed Hoekplaats Dolomite Mine area is located within the Aalwynkop dolomitic compartment. The Aalwynkop and Erasmia dolomitic compartments demonstrate a similar hydrostatic response pattern and are hydraulically connected along the Sesmylspruit to the east.

5.2.1. Groundwater Use Data sourced from the Department of Water Affairs and Forestry’s (DWAF) Water Authorisation and Registration Management System (WARMS) is summarised in Table 5.2. Table 5.2 Summary of WARMS groundwater use information – catchment A21B Authorized volume Topocadastral name Users 3 Water use sector (m /annum) Brakfontein 390 JR 1 6 720 Agriculture: irrigation Doornkloof 391 JR 4 1 143 856 Agriculture: irrigation Doornkloof 391 JR 3 340 444 Agriculture: irrigation Eldoraigne Ext 39 1 5 000 Industry (urban) Erand Agricultural Holdings 1 7 774 Agriculture: irrigation Erasmia 350 JR 1 101 000 Industry (urban) Exeter 137 JR 1 97 440 Agriculture: irrigation Garsfontein 374 JR 1 1 056 Agriculture: irrigation Glen Austin Agricultural Holdings 1 4 606 Agriculture: irrigation Halfway House Ext 16 1 3 650 Agriculture: irrigation Hennopspark Ext 16 1 500 Agriculture: irrigation Hoekplaats 384 JR 1 30 000 Agriculture: irrigation Knopjeslaagte 385 JR 7 273 548 Agriculture: irrigation Knopjeslaagte 385 JR 2 29 720 Agriculture: irrigation Lekkerhoekie 450 JR 1 3 125 Agriculture: irrigation Magaliesmoot Agricultural Holdings 1 12 050 Agriculture: irrigation Mooiplaats 355 JR 2 7 550 Agriculture: irrigation Olifantsfontein 410 JR 1 22 500 Agriculture: irrigation Olifantsfontein 410 JR 1 15 000 Agriculture: irrigation Schurveberg 488 JQ 1 147 825 Sterkfontein 401 JR 1 150 600 Sterkfontein 401 JR 3 9 360 Swartkop 383 JR 1 53 040 Sydney 136 JR 1 90 590 Timsrand Agricultural Holdings 1 324 Vlakplaats 354 JR 2 185 830 Witkoppies 393 JR 1 21 965 Zwartkop 356 JR 2 13 049 Total 45 2 778 422

The Tshwane Metropolitan Council’s groundwater use (22.7Mm3/a) for municipal water supply purposes are not listed in the WARMS data set (catchment A21B): 3  Boreholes situated in the Centurion area (catchment A21B) producing some 127L/s (4.01Mm /a);  The Sterkfontein spring (catchment A21B) which also drains catchment A21A produce some 82L/s (2.59Mm3/a);  The Pretoria Fountains, though situated to the north of catchment A21B, drains this catchment at a rate of roughly 304L/s (9.57Mm3/a);  The Aalwynkop and Erasmia dolomitic compartments support a number of distributed production boreholes delivering a combined yield of ±57L/s (1.80Mm3/a) for municipal water supply purposes.

5.2.2. Hydrocensus A limited hydrocensus was performed across the larger subject area. Apart from the Velmore Hotel which has a municipal water connection, a total of 9 points were surveyed (1 borehole on Ptn.23 of the farm Hoekplaats 384 JR [EUB-6] and 8 external users’ boreholes), all within a 1km radius of the Hoekplaats Dolomite Mine property. The reported total daily abstraction recorded within this 1km radius totals ±38 000 L/d (=38m3/d = 0.44L/s).

GROUNDWATER SQUARE Page 13 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

The surveyed boreholes are indicated in Figures 3.2, 3.3 and 4.1 and summarised in Table 5.3. A total of 5 water level measurements were recorded and one water sample was taken from the existing borehole on Ptn.23 of the farm Hoekplaats 384 JR. Borehole depths ranged between 18m and 32m (average 26m). Table 5.3 Basic hydrocensus information Borehole Owner Latitude Longitude Abstraction Groundwater Comments (WGS 84) (WGS 84) (L/day) level depth (m) EUB-1 Catwalk Brick Works 25.82702 28.05621 2 000 9.55 Submersible 32mm J. Niemandt Borehole depth = 32m Cell: 082 441 0003 2 000 L reservoir

EUB-2 The Cheese Shop 25.82750 28.05880 5 000 - Submersible 5.5Kw C. Koutzayiotis 2 x 5 000 L reservoirs Cell: 083 453 4291 EUB-3 Hoekplaats Boerdery 25.82652 28.05843 2 000 9.65 Submersible 0.75Kw J. Steinberg Borehole depth = 28m Cell: 082 572 9540

EUB-4 Bayete Day Spa 25.82021 28.05566 10 000 - Submersible 1.5Kw E. Maritz 3 x 5 000 L reservoirs Cell: 082 332 5475 EUB-5 Hennops Brick & Pave 25.82125 28.06378 2 000 12.68 Submersible 0.75Kw C. Visagie Borehole depth = 18m Cell: 073 695 4445 5 000 L reservoir EUB-6 Ptn.23 Hoekplaats 384 JR 25.82964 28.06311 1 667 8.99 Submersible P. Jubie 5 000 L reservoir Cell: 073 153 7054

EUB-7 Hennops Valley 25.82113 28.06944 15 000 - Submersible Nettie 2 x 5 000 L reservoirs Cell: 082 331 1705 EUB-8 Mooiplaas 25.82531 28.07396 2 000 - Submersible Lukas Smith 2 500 L reservoir Cell: 076 471 8436 EUB-9 Mooiplaas Nursery 25.82417 28.07619 20 000  12.5 Submersible 3.5Kw W.D. Bribnitz drought Cell: 082 461 6102

5.2.3. Depth to Groundwater Level and Hydrostatic Fluctuations Figure 5.1 depicts groundwater table elevations (August/September 2010) and depths for the larger study area. The following comments have relevance:

 The observed “steps” in the groundwater level across some of the dyke boundaries as well as the water elevations across the different response units, are highlighted: o A step in the depth to the water table of 16.2m across the Zwartkop dyke between DWA recorders A2N0757 and A2N0656 to the west of Valhalla; o A step of approximately 9m to 12m further to the south, north of the Sesmylspruit, between DWA recorders A2N0670 and A2N0669 as well as A2N0660 and A2N0659; o Historical information indicates a substantial step across the southeast trending dyke located immediately northeast of the Mooiplaats Dolomite Quarry (PPC); o An observation during 2002 indicated the water level elevation in the Mooiplaats Dolomite Quarry to be around 1347mamsl. This is lower than the groundwater levels observed around the proposed Hoekplaats Dolomite Mine – possibly indicative of localised de-watering around the Quarry;  The 5 water level measurements recorded during the hydrocensus ranged between 9.55m and 12.68m (average 10.67m) deep. The groundwater level depth in the on-site borehole (EUB-6) was recorded at 8.99m deep. The quarry is expected to be 40m deep. Consequently mining will occur ±30m below the natural groundwater table;  The Aalwynkop Spring which drains the Aalwynkop compartment is roughly located at an elevation of 1340mamsl representing the compartment’s decant elevation. By comparison: o The groundwater level in borehole EUB-6, which is situated within the proposed Hoekplaats Dolomite Mine property is ±1362.5mamsl (topography = 1371.5 and groundwater level = 8.99m deep), some 17.5m higher than the Aalwynkop Spring; o Assuming that the quarry will be 40m deep, the northern regions of the quarry floor is expected to be at lower elevations than the Aalwynkop Spring. GROUNDWATER SQUARE Page 14 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

To facilitate a comprehensive indication of the hydrodynamic responses in the compartmentalised groundwater regime, hydrograph records were sourced for some DWA groundwater monitoring stations across the study area for the period 1986 to 2010. The localities of recorders (A2N0656, A2N0657, A2N0659, A2N0660, A2N0669, A2N0670, A2N0674 and A2N0757) are depicted in Figure 5.1. Groundwater level information for the period August 1988 to August 2010 was plotted and represented in Figures 5.2A-C. Half of the hydrographs recorded a net rise in groundwater levels (0.52m to 0.77m); the other half a net drop in groundwater levels (-0.17m to -0.75m). The overall average mean net change is positive. No signs of prolonged (sustained) monthly declines are evident and no large scale abstraction impact is apparent. The observed fluctuations all fall within the natural hydrostatic fluctuation range (<5m) of a typical dolomitic groundwater environment.

Figure 5.1 Depth to water table and water level elevation distribution

Water Level Fluctuations A2N0660 A2N0669 A2N0670 A2N674 -4.00 -5.00 -6.00

) -7.00 m (

l -8.00 e v

e -9.00 l r e

t -10.00 a -11.00 W -12.00 -13.00 -14.00 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 8 8 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 ------g g g g g g g g g g g g g g g g g g g g g g u u u u u u u u u u u u u u u u u u u u u u A A A A A A A A A A A A A A A A A A A A A A Date Figure 5.2A Hydrostatic fluctuations in the Erasmia Compartment

GROUNDWATER SQUARE Page 15 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

Water Level Fluctuations A2N0657 A2N0659 -20.00 -22.00

-24.00

) -26.00 m (

l -28.00 e v

e -30.00 l r e

t -32.00 a -34.00 W -36.00 -38.00

-40.00 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 8 8 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 ------g g g g g g g g g g g g g g g g g g g g g g u u u u u u u u u u u u u u u u u u u u u u A A A A A A A A A A A A A A A A A A A A A A Date Figure 5.2B Hydrostatic fluctuations in the Erasmia Compartment

Water Level Fluctuations A2N0656 A2N0757

-47

) -52 m (

l e v e l -57 r e t a W -62

-67 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 8 8 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 0 ------g g g g g g g g g g g g g g g g g g g g g g u u u u u u u u u u u u u u u u u u u u u u A A A A A A A A A A A A A A A A A A A A A A Date Figure 5.2C Hydrostatic fluctuations in the Erasmia Compartment

5.2.4. Groundwater Flow Direction The direction of groundwater movement from the site is in a north-westerly direction towards the Hennops River and the Aalwynkop Spring which drains the Aalwynkop compartment.

5.2.5. Aquifer Yielding Potential The reported groundwater use from the existing borehole (EUB-6) on Ptn.23 of the farm Hoekplaats 384 JR equates to 0.46L/s for 1hour per day. The yielding potential for the proposed quarrying area proposed is considered to be low due to the anticipated low volume of effective storage. The dolomite to be mined is essentially chert-poor and the leaching is limited. The average leaching depth recorded in the 8 exploration boreholes drilled across the proposed area is 8.88mbs and only one of these boreholes recorded a water intersection.

5.2.6. Groundwater Quality The water quality results for the groundwater sample collected from borehole EUB-6 are summarised in Table 5.4. No variable exceeds the guideline concentration (SABS SANS 241:2006 Standard for Drinking Water). The hydro-chemical images (Piper and Durov plots), included as Figure 5.3, confirm the unimpacted nature of this groundwater sample. The ambient (background) groundwater quality for the Aalwynkop, Erasmia, West Fountain and the East and West Doornkloof dolomitic compartments, determined by the average of 13 samples

GROUNDWATER SQUARE Page 16 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) analysed for the West Fountain spring recorded between 2002 and 2004 (after Hobbs, Khulani 2004), are also included in Table 5.4. These concentrations also fall within the specified guideline concentrations.

Table 5.4 Water quality results for on-site borehole EUB-6 and ambient groundwater quality Ambient SANS 241 -2006 Domestic Water groundwater Class 1 Class II (Max Class II Water EUB – 6 Hoekplaats quality (Recommende Allowance for Consumption d Operational Limited Duration) Period, a max Limit) SAMPLED 2010/09/20 2002-2004 pH ( Laboratory) 7.6 7.6 5.0 - 9.5 4.0 - 10.0 No limit Conductivity (Laboratory) (mS/m) 70 45 < 150 150 - 370 7 years Total Dissolved Solids (mg/L) 323 283 < 1000 1000 - 2400 7 years Calcium (mg/L) 65 41 < 150 150 - 300 7 years Magnesium (mg/L) 39 27 < 70 70 - 100 7 years Sodium (mg/L) 3.8 12 < 200 200 - 400 7 years Potassium (mg/L) 0.69 < 50 50 - 100 7 years Chloride (mg/L) 5.2 29 <200 200 - 600 7 years Sulphate (mg/L) 30 19 <400 400 - 600 7 years Nitrate (mg/L) 2.0 2.0 < 10 10 - 20 7 years Nitrite (mg/L) 0.03 Total Alkalinity (mg/L) 285 206 Silicon (mg/L) 6.2 Ammonia (mg/L) 0.01 Ortho Phosphate (mg/L) <0.01 Fluoride (mg/L) 0.03 <1.0 1.0 - 1.5 1 year Iron (mg/L) <0.01 < 0.2 0.2 - 2.0 7 years Manganese (mg/L) <0.01 < 0.1 0.1 - 1.0 7 years Aluminium (mg/L) <0.01 <0.3 0.3-0.5 1 year Boron (mg/L) <0.01

Mg

80% 80%

60% 60%

40% 40% Ca Na+K T.Alk

20% 20%

SO4

Cations Anions

80% 20% 20% 80% Cl+NO3 EC [mS/m] (10-100)

60% 40% 40% 60%

pH (7-8) 40% 60% 60% 40%

20% 80% 80% 20%

80% 60% 40% 20% 20% 40% 60% 80% Calcium Chloride & Nitrate Piper plot Durov plot Figure 5.3 Piper and Durov image plots of the water quality in the proposed mining area as sampled from borehole EUB-6

GROUNDWATER SQUARE Page 17 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

5.2.7. Surface Water Quality Surface water drainage impacting on dolomitic groundwater quality is a distinct reality. The water quality of the surface water drainage system which features several diffuse and point pollution sources across the larger study area is important and warrants elaboration. Hydro-chemical data was obtained for two of the Department of Water Affairs and Forestry’s Water Manage System (WMS) Resource Quality Services (RQS) monitoring sites (WMS A21_100000768 [Hennops River @ Bridge on M26 – below Sunderland Ridge Sewage Works] and WMS A21_100000773 [Swartbooispruit @ Bridge on M26 – before confluence with Hennops]) for the period 2002-06-18 to 2009-07 (See Figure 3.2). A statistical analysis of selected variables is presented in Table 5.5. Results exceeding the SABS SANS 241:2006 Standard for Drinking Water, are also indicated. Time dependent hydro-chemistry graphs for WMS sampling localities A21_100000768 and A21_100000773 are presented in Figures 5.4A-C.

 The following comments have relevance:  The Hennops River upstream of the proposed Hoekplaats Dolomite Mine is indicative of: o Average ammonia concentrations exceeding Class II (max. allowable for limited duration); o Average nitrate concentration, although compliant is elevated and the average ortho- phosphate concentration exceeds the wastewater special limit value applicable to discharge of wastewater into a water resource as outlined in the General Authorisation promulgated in Gazette no.26187, Notice no. 399 (published on 26 March 2004 in terms of the National Water Act, Act No. 36 of 1998); o The upstream Hennops River EC trend is sideways, and while the nitrate trend is improving the ammonia trend is deteriorating;  The Swartbooispruit: o Although the listed average concentrations for Swartbooispruit are all compliant with the Drinking Water specifications, some concentrations exceed the Class I quality range (Ca and Mg), the Class II range (NH4) and the wastewater special limit value (PO4); o An improving trend is noted for EC and NO3 and a deteriorating trend for NH4;  It is clear that the surface water in the study area is of a poorer quality than the background dolomitic groundwater.

Table 5.5 WMS water quality interpretation (June 2002 to July 2009) WMS A21_100000768 WMS A21_100000773 Hennops River Swartbooispruit Variable Min Max Ave 95%ile Min Max Ave 95%ile pH 7.1 8.8 7.57 7.97 7.3 8.5 7.98 8.3 EC (mS/m) 34 108 68 83 27 97 76 88 Ca (mg/l) 13 61 35.07 47 7 152^ 63.63 88 Mg (mg/l) 8 50 15.28 22.1 11 89^ 43.84 60 NO3(N) 0.05 9.5 4.1 7.3 0.05 5 1.5 4.5 NH4 0.02 19.3+ 5.06+ 12.73+ 0.05 6+ 0.34 0.7 PO4 0.05 4.15 1.45 3.27 0.014 1.1 0.08 0.3 SO4 5 132 57 83 25 259 46 69 Tot.Alk 87 379 170 240.25 107 466 360 431 Class I (recommended operational limit) ^ Class II (max. allowable for limited duration) + Class II is exceeded

GROUNDWATER SQUARE Page 18 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

Electrical Conductivity Trend

120

100

80 ) m S

m 60 (

C E 40

20

0 13-Feb-02 20-Mar-03 23-Apr-04 28-May-05 02-Jul-06 06-Aug-07 09-Sep-08 Date

WMS A21_100000773 Swartbooispruit WMS A21_100000768 Hennops River Figure 5.4A EC variations over time

Nitrate Concentration Trend

10 9 8 7 ) l / 6 g m

( 5

3

O 4 N 3 2 1 0 13-Feb-02 20-Mar-03 23-Apr-04 28-May-05 02-Jul-06 06-Aug-07 09-Sep-08 Date

WMS A21_100000773 Swartbooispruit WMS A21_100000768 Hennops River Figure 5.4B Nitrate variations over time

Ammonia Concentration Trend

20 18 16 14 ) l

/ 12 g m

( 10

4

H 8 N 6 4 2 0 13-Feb-02 20-Mar-03 23-Apr-04 28-May-05 02-Jul-06 06-Aug-07 09-Sep-08 Date

WMS A21_100000773 Swartbooispruit WMS A21_100000768 Hennops River Figure 5.4C Ammonia variations over time GROUNDWATER SQUARE Page 19 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) 6. POTENTIAL IMPACTS A mine closure impact rating system, known as “RISKY” was developed by the Institute for Groundwater Studies at the University of the Orange Free State. The software can be used to evaluate the potential impact of a quarry for industrial mineral recovery such as quartz, calcite or dolomite. These types of mining operations will most-likely not pose a threat to the environment. The selected categories for a typical small-scale operation of this kind are illustrated in Figures 6.1 and 6.2. Taking cognisance of this first approximation evaluation, the potential impact related to the proposed 15 ha dolomite mine on Ptn.23 of the farm Hoekplaats 384 JR is identified and discussed below.

Figure 6.1 Impact assessment on mine/water relationship for silica mining

Figure 6.2 Impact assessment on mine/aquifer relationship for silica mining

GROUNDWATER SQUARE Page 20 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) 6.1. Identification of Potential Impacts The potential impacts on groundwater quality are:

 Mining vehicles, mechanical equipment, workshops and fuel facilities may generate diesel/oil leakages/spillages;  Domestic waste may introduce various types of organic and inorganic contamination (at small volumes).  Sanitation facilities might pose a localized nitrate and bacteriological contamination problem if a municipal connection is not possible;  Possible nitrate contamination may also result from: o Rock blasting; o The settlement dam.

The potential impacts on the groundwater quantity primarily relate to the dewatering of the quarry, specifically:

 A localized groundwater dewatering cone may manifest around the pit and impact on the yielding capacity of the external user’s boreholes;  A certain volume of groundwater base-flow toward the Hennops River and Aalwynkop Spring will be intercepted.

6.2. Discussion of Potential Impacts The following management/mitigation measures, if thoroughly designed, should mitigate most of the contamination impacts:

 Surface water run-off should be controlled in-and-around the proposed plant, quarry, and settlement pond by a combination of diversion berms and trenches;  The fuel storage/transfer areas, workshop areas, contract serviced oil separators and contractually serviced portable chemical toilets, should be bund-walled ;  Surface water should be allowed to remain unimpacted, draining freely from the site;  The design of the settlement pond liner should be based on: o Responsible industry standards; o The expected water quality; o Preventing any unnecessary water losses to the subsurface (i.e. water infiltrating through permeable soil);  Proper monitoring should timeously confirm any impacts on the local groundwater quality.

It is likely that a dilution effect will reduce blasting related (increased nitrate concentrations) impacts on the groundwater quality; Once the mine intersects the natural groundwater table, groundwater will be pumped from the pit, potentially impacting on the yielding capacity of the two external user borehole’s to the immediate west of Ptn.23 (EUB-1 & EUB-2). In view of the probable compartmentalisation effect of the Zwartkop dyke (depending on its weathering status) and the anticipated low yielding capacity of the shallow aquifer (being chert-poor, <40m), the impact on the Hennops River and neighbouring boreholes to the north of the property may potentially be insignificant.

GROUNDWATER SQUARE Page 21 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10)

7. RECOMMENDATIONS It is recommended that the potential impact from the de-watering of the quarry be quantified through a numeric groundwater model, populated with site specific data. This will entail:

 Dedicated hydrogeological boreholes should be drilled: o Four to six boreholes may be required; o Drilled to various depths ranging between 20m and 50m; o Optimally placed across the site, to include testing of the Zwartkop dyke and the aquifer;  Hydrogeological boreholes should be pump-tested to determine: o Hydraulic aquifer parameters; o The compartmentalising effect of the Zwartkop dyke;

In future, the proposed hydrogeological boreholes can be used for:

 Dewatering the dolomite rock ahead of mining (resulting in dry in-pit conditions);  Groundwater monitoring forming part of the groundwater management strategy required for the Catchment Management Strategy (CMS).

______Louis Botha (M.Sc., Pr.Sci.Nat.) for GROUNDWATER SQUARE file: GW2_215Hoelplaats_GroundwaterAssess_rep.doc

GROUNDWATER SQUARE Page 22 HOEKPLAATS Dolomite (Pty) Ltd – Preliminary Groundwater Assessment: Portion 23 (a Portion of Portion 15) of the farm Hoekplaats 384 JR Ref:215_Hoekplaats (Oct’10) References

Chief Directorate: Surveys and Mapping. The 1:50 000 Series Topographical Maps 2528CC, CD & DC, 2628AA, AB, AD & DA. Council for Geoscience, 1978. 1:250 000 Geological Maps, 2528 Pretoria. DWAF, 1995. Groundwater Resources of the Republic of South Africa, SHEET 1 & SHEET 2. DWAF, 1999. 1: 500 000 Geohydrologcial map series of the Republic of South Africa, Sheet 2526 Johannesburg. DWAF, October 2000. An Explanation of the 1:500 000 General Geohydrologcial Map Johannesburg 2526, HC Barbard. DWAF, 1996. Groundwater Harvest Potential of the Republic of South Africa. DWAF, 2002. Republic of South Africa Water Management Areas - Water Availability and Requirements. DWAF, 2003. Municipal Demarcations of the Republic of South Africa, Task No. Gm653_03. Midgley DC, Pitman WV, Middleton BJ, 1994. Surface Water Resources of South Africa 1990, Book of Maps, Volume II, WRC Report No 298/2.2/94. Parsons R, 1995. A South African Aquifer System Management Classification, WRC Report No KV 77/95 Schulze RE, 1997. South African Atlas of Agrohydrology and Climatology, ACRU Report No 46. Jones & Wagener, 2004. First Interim Report on Sinkholes at Bapsfontein. Report No. JW21/04/9401.

Bredenkamp, DB, 1995. Dolomitic Groundwater Resources of the Republic of South Africa. Report No. GH 3857. DWAF.

DWAF. East Rand Dolomite Project, December 1984 – October 1986.

Bredenkamp, DB, Botha, L.J., Van Tonder, G.J. and Van Rensburg, H.J., 1995. Manual on Quantitative Estimation of Groundwater Recharge and Aquifer Storativity based on Practical Hydro- Logical Methods. Water Research Commission. Pretoria.

JMA, June 2005. Formation of Sinkholes in the Bapsfontein Area - Geohydrological Aspects. Ref. No. 10275.

Bredenkamp DB, Van der Westhuizen C, Wiegmans FE & Kuhn CM, June 1986. Ground-Water Supply Potential of Dolomite Compartments West of Krugersdorp, DWAF Technical Report No: GH 3440.

PJ Hobbs Khulani Joint Venture, August 2004. Intermediate Groundwater Reserve Determination For Quaternary Catchments A21A & A21B. Project No. 2002-316.

Sami, K, 2003. Pollution Potential of the Grootfontein Spring and the Rietvlei Boreholes. Mothopong Consulting (Pty) Pretoria.

Dr. Fritz Wagener. Sinkholes in the Bapsfontein dolomite water compartment caused by dewatering, Civil Engineering, Vol. 17 No. 3, April 2009. DWAF, Internal Strategic Perspective: Crocodile West Marico Water Management Area - Crocodile River (West)Catchment, Version 1: February 2004. Hodgson FDI; Usher BOREHOLE, Scott R, Zeelie S, Cruywagen L-M, de Necker E, 2001. Prediction techniques and preventative measures relating to the post-operational impact of underground mines on the quality of groundwater resources. WRC Report No: 699/1/01. ISBN No: 1-86845-701-X.

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